U.S. patent application number 13/044008 was filed with the patent office on 2011-09-22 for vibrator in vibration type driving apparatus and manufacturing method thereof.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Yasuyuki Araki, Hiroyuki Seki.
Application Number | 20110227454 13/044008 |
Document ID | / |
Family ID | 44603037 |
Filed Date | 2011-09-22 |
United States Patent
Application |
20110227454 |
Kind Code |
A1 |
Araki; Yasuyuki ; et
al. |
September 22, 2011 |
VIBRATOR IN VIBRATION TYPE DRIVING APPARATUS AND MANUFACTURING
METHOD THEREOF
Abstract
A vibrator which constitutes a vibrating device of a
vibration-type driving apparatus which comprises the vibrating
device bonded to an electromechanical-energy-conversion element and
comprising the vibrator having a projection portion, in which the
vibrating device is constituted so that elliptic motion can arise
at the projection portion by applying an alternating electric field
to the electromechanical-energy-conversion element, and which moves
by the elliptic motion a driven object being in contact with the
projection portion in a direction intersecting with a width
direction, wherein the vibrator comprises a base and the one/plural
projection portions, the projection portion has at least two wall
portions extending in a base out-of-plane direction and a contact
portion having a contact surface with the driven object, and the
contact surface connects the wall portions, and in boundary
portions between the base and the wall portions, displacement
directions are at a same position in a normal direction.
Inventors: |
Araki; Yasuyuki;
(Kawasaki-shi, JP) ; Seki; Hiroyuki; (Oyama-shi,
JP) |
Assignee: |
CANON KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
44603037 |
Appl. No.: |
13/044008 |
Filed: |
March 9, 2011 |
Current U.S.
Class: |
310/323.16 ;
29/25.35 |
Current CPC
Class: |
H02N 2/0015 20130101;
Y10T 29/42 20150115; H02N 2/026 20130101 |
Class at
Publication: |
310/323.16 ;
29/25.35 |
International
Class: |
H02N 2/04 20060101
H02N002/04; H01L 41/22 20060101 H01L041/22 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2010 |
JP |
2010-058779 |
Nov 24, 2010 |
JP |
2010-261582 |
Jan 18, 2011 |
JP |
2011-007695 |
Claims
1. A vibrator which constitutes a vibrating device of a vibration
type driving apparatus which comprises the vibrating device bonded
to an electromechanical energy conversion element and comprising
the vibrator having a projection portion thereon, in which the
vibrating device is constituted so that elliptic motion can arise
at the projection portion of the vibrator by application of an
alternating electric field to the electromechanical energy
conversion element, and which moves by the elliptic motion an
object to be driven being in contact with the projection portion of
the vibrator in a direction intersecting with a width direction of
the vibrator, wherein the vibrator comprises a base and the one or
the plural projection portions, the projection portion is formed by
at least two wall portions which extend in an out-of-plane
direction of the base and a contact portion which has a contact
surface with the object to be driven, and the contact surface
connects the wall portions with each other, and in boundary
portions between the base and the respective wall portions,
directions of displacement are provided at a same position in a
normal direction on a main surface of the base.
2. The vibrator according to claim 1, wherein the projection
portion has a hollow construction which is formed by the base, at
least the two wall portions, and the contact portion connecting the
wall portions with each other.
3. The vibrator according to claim 1, wherein the contact portion
has springiness.
4. The vibrator according to claim 1, wherein the wall portion is
formed by a plate member which has a predetermined width and a
predetermined thickness, the predetermined width being larger than
the predetermined thickness, and the plate member is formed so that
a thickness direction of the plate member is pointed toward the
width direction of the vibrator, and a width direction of the plate
member is pointed toward the direction intersecting with the width
direction of the vibrator.
5. The vibrator according to claim 1, wherein a through hole is
formed in a partial region of the base positioned between the
projection portion and the electromechanical energy conversion
element.
6. The vibrator according to claim 1, wherein the projection
portion is formed integrally with the vibrator by a member
constituting one base, through plural slits or notches formed on
the base.
7. The vibrator according to claim 1, wherein a displacement
direction of a central portion of the base in the normal direction
is same as the displacement direction of the boundary portion.
8. A manufacturing method of a vibrator which constitutes a
vibrating device of a vibration type driving apparatus which
comprises the vibrating device bonded to an electromechanical
energy conversion element and comprising the vibrator having a
projection portion thereon, in which the vibrating device is
constituted so that elliptic motion can arise at the projection
portion of the vibrator by application of an alternating electric
field to the electromechanical energy conversion element, and which
moves by the elliptic motion an object to be driven being in
contact with the projection portion of the vibrator in a direction
intersecting with a width direction, the manufacturing method
comprising: preparing one member to integrally form the projection
portion and the vibrator, and forming plural slits or notches in a
partial region of the member; and forming, by using a part of a
portion positioned between the slits or the notches, the projection
portion by a bending process or a drawing process.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vibrator in a vibration
type driving apparatus and a manufacturing method thereof. More
particularly, the present invention relates to a vibrator in a
linear ultrasonic motor (vibration type driving apparatus) and a
manufacturing method thereof.
[0003] 2. Description of the Related Art
[0004] Conventionally, as a linear ultrasonic motor which linearly
drives an object to be driven, a vibration type driving apparatus
as disclosed in U.S. Pat. No. 7,109,639 has been proposed.
[0005] Here, a driving principle of the linear ultrasonic motor
(vibration type driving apparatus) like this will be described with
reference to the drawings.
[0006] As shown in FIG. 8A which is a perspective view illustrating
an exterior appearance of the linear ultrasonic motor, a linear
ultrasonic motor 510 is constituted by a vibrating device 501, a
slider 506, and a pressurizing member (not illustrated) for
pressurizing the vibrating device toward the slider.
[0007] The vibrating device 501 is constituted by an
electromechanical energy conversion element 505 such as a
piezoelectric element or the like, and a vibrator which is
integrally bonded to one surface of the electromechanical energy
conversion element 505. Here, the vibrator includes a base 502
which is formed rectangularly, and two projection portions 503 and
504 which are formed convexly on the upper surface of the base.
[0008] In the ultrasonic motor, if a voltage of a specific
frequency (also, called an alternating electric field) is applied
to the piezoelectric element, plural desired vibration modes are
excited, and then the excited vibration modes are superimposed,
thereby generating a vibration for driving.
[0009] The linear ultrasonic motor illustrated in FIG. 8A causes
the vibrating device 501 to perform excitation of two bending
vibration modes respectively illustrated in FIGS. 8B-1 and 8B-2.
Both the two bending vibration modes are out-of-plane bending
vibration modes of the plate-like vibrating device 501.
[0010] More specifically, one of the two out-of-plane bending
vibration modes is a second-order bending vibration mode (MODE-A:
feeding mode) in the longitudinal direction of the vibrating device
501, and the other of the two out-of-plane bending vibration modes
is a first-order bending vibration mode (MODE-B: upthrust mode) in
the width direction of the vibrating device 501.
[0011] The shape of the vibrating device 501 is designed so that
the resonance frequencies of the two out-of-plane bending vibration
modes coincide with each other or come close to each other.
[0012] Each of the projection portions 503 and 504 is disposed in
the vicinity of a position which is a node of vibration in the
vibration of the MODE-A (feeding mode). Then, each of apical
surfaces 503-1 and 504-1 of the projection portions performs
pendular motion using the node of the vibration as a fulcrum by
means of the vibration of the MODE-A, whereby the apical surfaces
perform reciprocation motion in the X direction (feeding
direction).
[0013] Further, each of the projection portions 503 and 504 is
disposed in the vicinity of a position which is an anti-node (or a
loop) of vibration of the MODE-B (upthrust mode). Thus, the apical
surfaces 503-1 and 504-1 of the projection portions perform
reciprocation motion in the Z direction (upthrust direction, or
normal-line direction) by means of the vibration of the MODE-B.
[0014] These two vibration modes (MODE-A and MODE-B) are
simultaneously excited so that a vibration phase difference between
these modes comes near .+-..pi./2, and these modes are then
superimposed, whereby elliptic motion in the X-Z plane arises at
each of the apical surfaces 503-1 and 504-1.
[0015] Thus, the slider 506 which has been pressurized and brought
into contact with the vibrating device can be driven in one
direction by means of the relevant elliptic motion. At this time,
the projection portions 503 and 504 of the vibrating device 501 and
the slider 506 repetitively make contact and non-contact at the
driving frequency (tens of kilohertz or more) of the vibrating
device 501. For this reason, if one of these elements does not have
an appropriate spring characteristic, a satisfactory contact state
cannot be obtained.
[0016] On the other hand, as described above, each of the
projection portions 503 and 504 has such a function of amplifying
the vibration in the X direction.
[0017] To satisfy the above-described two functions, United States
Patent Application Publication US2009/167111 proposes a vibration
type actuator (linear ultrasonic motor) which achieves quiet
driving. Namely, in this vibration type actuator, as illustrated in
FIGS. 9A to 9C, springiness is given to each of the projection
portions, and each of the projection portions is designed to have
an appropriate shape.
[0018] More specifically, in this vibration type actuator,
projection portions 609 and 610 each of which has springiness is
formed as additional members, and bonded to a base 602, whereby a
vibrating device 601 is formed.
[0019] However, in the vibration type actuator described in United
States Patent Application Publication US2009/167111, there is a
limit to speeding up of a motor, as described later. Here, as one
measure of driving a motor at higher speed, there is a method of
enlarging a vibration amplitude of the projection of the vibrating
device in a feeding direction (X direction).
[0020] Further, as one of the methods of enlarging the vibration
amplitude of the projection in the feeding direction (X direction),
there is a method of increasing the height of the projection.
[0021] However, in the vibration type driving apparatus described
in U.S. Pat. No. 7,109,639, although speeding up can be achieved if
the height of the projection is increased, it is not avoided that
costs increase in a manufacturing process.
[0022] In the vibration type actuator described in United States
Patent Application Publication US2009/167111, if the height of the
projection portion of the vibrating device is increased, the
rigidity of the projection portion decreases in the feeding
direction, whereby driving efficiency decreases. Moreover, it
becomes difficult to set a vibration angle of the apex of the
projection portion to a desired value in the feeding mode. As a
result, unnecessary amplitude arises in the Z direction, whereby
there is a fear that contact between the projection portion and the
slider becomes unstable.
[0023] The present invention has been completed in consideration of
such problems as described above, and an object of the present
invention is to provide a vibrator in a vibration type driving
apparatus in which the vibrator capable of achieving speeding up
can be manufactured at low cost and a manufacturing method of the
vibrator.
SUMMARY OF THE INVENTION
[0024] According to one aspect of the present invention, there is
provided a vibrator which constitutes a vibrating device of a
vibration type driving apparatus which comprises the vibrating
device bonded to an electromechanical energy conversion element and
comprising the vibrator having a projection portion thereon, in
which the vibrating device is constituted so that elliptic motion
can arise at the projection portion of the vibrator by application
of an alternating electric field to the electromechanical energy
conversion element, and which moves by the elliptic motion an
object to be driven being in contact with the projection portion of
the vibrator in a direction intersecting with a width direction of
the vibrator, wherein the vibrator comprises a base and the one or
the plural projection portions, the projection portion is formed by
at least two wall portions which extend in an out-of-plane
direction of the base and a contact portion which has a contact
surface with the object to be driven, and the contact surface
connects the wall portions with each other, and, in boundary
portions between the base and the respective wall portions,
directions of displacement are provided at a same position in a
normal direction on a main surface of the base.
[0025] According to another aspect of the present invention, there
is provided a manufacturing method of the above-described vibrator
which constitutes the vibrating device of the vibration type
driving apparatus, the manufacturing method comprising: preparing
one member to integrally form the projection portion and the
vibrator, and forming plural slits or notches in a partial region
of the member; and forming, by using a part of a portion positioned
between the slits or the notches, the projection portion by a
bending process or a drawing process. According to the present
invention, it is possible to achieve the vibrator in the vibration
type driving apparatus in which the vibrator capable of achieving
speeding up can be manufactured at low cost and the manufacturing
method of the vibrator.
[0026] Further features of the present invention will become
apparent from the following description of the exemplary
embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view for describing a vibrator of a
vibration type driving apparatus (linear ultrasonic motor)
according to the first embodiment of the present invention.
[0028] FIG. 2 is a view for describing the vibrator of the
vibration type driving apparatus according to the first embodiment
of the present invention.
[0029] FIGS. 3A and 3B are views for describing a vibrator of a
vibration type driving apparatus according to the second embodiment
of the present invention.
[0030] FIGS. 4A and 4B are views for describing a vibrator of a
vibration type driving apparatus according to the third embodiment
of the present invention.
[0031] FIGS. 5A and 5B are views for indicating a third-order
upthrust mode according to the fourth embodiment of the present
invention.
[0032] FIGS. 6A and 6B are views for describing a vibrator of a
vibration type driving apparatus according to the fifth embodiment
of the present invention.
[0033] FIGS. 7A and 7B are cross-sectional views for describing a
first-order bending mode (upthrust mode) of the vibrator according
to the first embodiment of the present invention, where FIG. 7A is
the view for describing a case where a boundary surface between a
projection portion and a base is set between nodes in vibration of
the first-order bending mode in the Y direction, and FIG. 7B is the
view for describing a case where the boundary surface is set
outside the respective nodes in vibration of the first-order
bending mode.
[0034] FIGS. 8A, 8B-1 and 8B-2 are views for describing the
conventional vibration type driving apparatus (linear ultrasonic
motor), where FIG. 8A is the perspective view illustrating the
exterior appearance of the linear ultrasonic motor described in
U.S. Pat. No. 7,109,639, and FIGS. 8B-1 and 8B-2 are the views
indicating vibration modes with which vibration is excited by the
vibrating device of the relevant linear ultrasonic motor.
[0035] FIGS. 9A, 9B and 9C are views for describing the
conventional vibration type actuator (linear ultrasonic motor)
described in United States Patent Application Publication
US2009/167111, where FIG. 9A is the perspective view of the
vibrating device, FIG. 9B is the enlarged view of the projection
portion, and FIG. 9C is the cross-sectional view of the projection
portion.
DESCRIPTION OF THE EMBODIMENTS
[0036] The exemplary embodiments of the present invention will be
described hereinafter.
First Embodiment
[0037] As the first embodiment, an example of the constitution of a
vibrator for constituting a vibrating device of a vibration type
driving apparatus, to which the present invention is applied, will
be described with reference to FIGS. 1 and 2.
[0038] The vibrating device in the present embodiment, which is
bonded to an electromechanical energy conversion element, has the
vibrator on which one or more projection portions are formed.
[0039] This vibrating device is characterized in that the
projection portions of the vibrator move with such a state of
tracing an ellipsoidal trajectory within the X-Z plane depending on
the synthesis of vibration of a first-order bending vibration mode
in the width direction of the vibrator and vibration of a
second-order bending vibration mode in the direction orthogonal to
the width direction of the vibrator by an operation of applying an
alternating electric field to the electromechanical energy
conversion element.
[0040] Herewith, an object to be driven which was contacted with
the projection portions of the vibrator can be moved to the
direction of intersecting (typically, orthogonally intersecting)
with the width direction by frictional driving.
[0041] More specifically, a vibrating device 111 of the present
embodiment is constituted by a piezoelectric element 107 serving as
the electromechanical energy conversion element formed in a
rectangular thin plate shape and a vibrator 101 to be united bonded
to the one end surface of this piezoelectric element 107 as
indicated in FIGS. 1 and 2.
[0042] Two projection portions 109 and 110 to be contacted with a
slider (not illustrated) serving as an object to be driven are
provided on the vibrator 101, and the slider is compressively
contacted with the vibrator 101 through the projection portions 109
and 110.
[0043] When applying an alternating electric field to the
piezoelectric element 107, the vibration by two bending vibration
modes are excited at the vibrating device 111, and the vibration of
elliptic motion is excited on contact surfaces on the projection
portions 109 and 110.
[0044] As a result, the slider which is compressively contacted
with the projection portions 109 and 110 receives frictional
driving force and is driven to the X direction (feeding
direction).
[0045] Here, the constitution of the vibrator 101 which constitutes
the above-described vibrating device 111 will be described with
reference to FIG. 2.
[0046] The vibrator 101 is constituted by a base 102 and the
projection portions 109 and 110. These projection portions 109 and
110 are formed in the vicinity of nodes of a second-order bending
mode (feeding mode) similar to a case in FIG. 8B-1 indicated in the
related background art.
[0047] Here, each of the projection portions 109 and 110 is
constituted by two wall portions 14a and 14b and a contact portion
16 for connecting the two wall portions with each other. In the
present embodiment, although the two wall portions are provided,
the wall portions may be increased in accordance with necessity.
For example, each of the wall portions 14a and 14b can be divided
into plural portions each other by providing slits or the like in
between them.
[0048] A contact surface to be compressively contacted with the
slider is formed on a surface of the contact portion 16.
[0049] The two wall portions 14a and 14b provided on the base 102
are in the same Z-Y plane. The wall portions are formed with such a
state of extending to an out-of-plane direction of the
above-described base, typically extending to the vertical direction
against the base. However, it is not always required to extend to
the vertical direction but can be constituted to have a certain
inclined angle in accordance with necessity. Here, it should be
noted that the "an out-of-plane direction" means such the direction
which is not parallel to a main surface (a surface on which the
above-described projection portions are formed) of the
above-described base.
[0050] Namely, the projection portions 109 and 110 have two base
roots collaterally set in the parallel direction to the direction
(Y direction) of intersecting (typically, vertically intersecting)
with the feeding direction (X direction). In the present invention,
the "parallel" means a case of the strict parallel or it is allowed
to shift from the parallel within a range of not giving a practical
problem to the vibration property as well as a case of the design
error. For example, even if it is shifted by 10 degrees from the
parallel, such the inclination is tolerated in a case where the
desired vibration can be obtained.
[0051] The wall portions are formed with a state of having the
predetermined width and thickness. In the present embodiment, each
of the wall portions is formed by a plate member of which the width
is larger than the thickness, and it is formed that the thickness
direction of the plate member is faced to the width direction of
the vibrator and the width direction of the plate member is faced
to the direction orthogonal to the width direction of the
vibrator.
[0052] By adopting such the constitution, the thickness direction
of the wall portions 14a and 14b becomes the Y direction, and since
the width of the wall portions 14a and 14b becomes larger to the X
direction, the projection portions 109 and 110 secure the
predetermined rigidity to the X direction.
[0053] FIG. 7A is a cross-sectional view regarding a first-order
bending mode as a result of performing an FEM (Finite Element
Method) analysis with a state that the vibrator is bonded to the
piezoelectric element, and FIG. 7B is a cross-sectional view
regarding a second-order bending mode for the same analysis.
[0054] In case of the first-order bending mode of the present
embodiment, as indicated in FIG. 7A, it is desirable that boundary
portions 18a and 18b between the wall portions of the projection
portion and the base 102 of the vibrator are located between nodes
13a and 13b in vibration of the first-order bending mode (upthrust
mode) for the Y direction.
[0055] That is, it is desirable that the boundary portions 18a and
18b between the projection portions and the base are located at
such places (positions), where the displacement directions of the Z
direction (upthrust direction/normal direction) on a main surface
of the base become the same direction each other in the first-order
bending mode (upthrust mode). In case of the present embodiment,
the boundary portions 18a and 18b between the projection portions
and the base are located at such places (positions), where the
displacement directions also become the same direction as that of
the Z direction of a central portion of the base. In the present
invention, the above-described "positions where the displacement
directions become the same direction each other" means such the
positions which are in such a condition of displacing to the same
direction in a case where an arbitrary moment is extracted at the
time of vibration of the vibrator. That is, these positions are
such the positions which are in such a condition of displacing to
the same direction at the same moment. Typically, the displacement
between adjacent nodes is the same directional displacement. On the
contrary, in a case where nodes are positioned in the order of A, B
and C, the direction of the displacement between nodes A and B
becomes inverse to the direction of the displacement between nodes
B and C.
[0056] In the present invention, a fact of displacing to the Z
direction (upthrust direction/normal direction) on a main surface
of the base means that it is allowed that the component of the Z
direction (upthrust direction/normal direction) on a main surface
of the base is included in the displacement direction of that
displacing portion.
[0057] Also, in the present invention, the boundary portions 18a
and 18b can be provided at the outside of the nodes 13a and 13b in
vibration of the first-order bending mode as indicated in FIG. 7B.
In this case, since the deformation direction of a central portion
of the base becomes opposite to the deformation direction of a
central portion of a contact surface of the projection portion as
compared with the case in FIG. 7A, although there is sometimes a
case where transmission efficiency of force to the Z direction is
relatively decreased when a contact surface of the projection
portion contacts with the slider, there is not a practical problem.
There is the significance in a point that design flexibility of the
boundary portion between the projection portion and the base can be
improved. However, also in this case, it is required that the
boundary portions between the projection portions and the base are
located at such places (positions), where the displacement
directions of the Z direction (upthrust direction/normal direction)
on a main surface of the base become the same direction each other.
If the boundary portions between the projection portions and the
base are located at such places (positions), where the displacement
directions of the Z direction (upthrust direction/normal direction)
on a main surface of the base become different (inverse) direction
each other, the force transmission to the Z direction becomes
unstable when the contact surface of the projection portion
contacts with the slider, and stable driving cannot be obtained. As
a specific example, it is a case where the boundary portion between
the projection portion and the base is set with a state of crossing
over the node 13b in FIG. 7A.
[0058] In the constitution illustrated in FIG. 2, the better
contact condition between the vibrating device 111 and the slider
can be realized by additionally giving springiness to the slider. A
stable contact condition can be also realized by giving springiness
to the contact portion without giving springiness to the slider. In
this manner, by giving springiness to, at least, one of the slider
or the contact portion, the contact condition for each of the
vibrating device and the slider can be well maintained. In
addition, even if height of the projection portions 109 and 110 is
increased for the purpose of speeding up of driving, since the
rigidity to the X direction, which is equivalent to the drive
direction of the slider, of the projection portions 109 and 110 is
secured by the wall portions 14a and 14b, a drive force of the
vibrating device 111 can be efficiently transmitted to the
slider.
[0059] In addition, as compared with a vibrator 501 having
projection portions 503-1 and 504-1 indicated in FIG. 8A, the
projection portion is formed to become the hollow construction
surrounded by the base, the two wall portions and the contact
portion which connects the one wall portion with the other wall
portion between them.
[0060] Thus, since a space is held under the contact portion, the
bending rigidity with an upthrust mode becomes to be decreased, and
the electric power efficiency can be improved.
[0061] It should be noted that the width of the wall portions 14a
and 14b may not be equal to the width in the X direction of the
contact portion 16.
[0062] Also, the width of the wall portion 14a and the width of the
wall portion 14b are not required to be the same along the Z
direction.
[0063] For example, when the width of the wall portions 14a and 14b
close to the base 102 is formed to become wider, the width of the
wall portions 14a and 14b close to the contact portion 16 is formed
to become narrower and the mean width of the wall portions 14a and
14b is formed to become wider, the rigidity of the wall portions
14a and 14b in the X direction can be increased.
[0064] As the manufacturing method of the vibrator according to the
present embodiment, the vibrator can be manufactured by a process
that, for example, the projection portions 109 and 110 are once
formed and then these projection portions 109 and 110 are formed on
the base 102 by a bonding method such as the laser welding or the
adhesion.
Second Embodiment
[0065] As the second embodiment, an example of the constitution of
a vibrator of which projection portions are integrally formed
together with a base by performing a drawing process after
providing plural slits or notches on the base will be described
with reference to FIGS. 3A and 3B.
[0066] In the present embodiment, as illustrated in FIG. 3A, a
through hole 21 is provided at a partial area of a base 202 under a
contact portion 26 of a vibrator 201 differently from the case of
the first embodiment.
[0067] Consequently, as illustrated in FIG. 3B, slits 22 are
provided on both sides of a portion where the drawing process is
performed. Then, by performing the drawing process, the vibrator
201 which includes the projection portions can be integrally formed
at a low cost.
[0068] It is enough by the little energy to generate the upthrust
vibration by providing the through hole 21 at a partial area of the
base 202. As a result, the drive efficiency can be improved.
Third Embodiment
[0069] As the third embodiment, an example of the constitution of a
vibrator in a vibration type driving apparatus characterized by a
mode different from the modes of the above-described respective
embodiments will be described with reference to FIGS. 4A and
4B.
[0070] In the present embodiment, a through hole 31 is provided
under a contact portion 36 of a vibrator 301 and a slit 32 is
provided at the same time such that a base 302 is separated into
two parts when projection portions are removed, differently from
cases of the above-described respective embodiments.
[0071] According to this constitution, the vibrator which includes
the projection portions can be integrally formed by a bending
process.
[0072] It is enough by the little energy to generate the upthrust
vibration by providing the through hole 31 and the slit 32 at
partial areas of the base 302. As a result, the drive efficiency
can be improved.
[0073] In the present embodiment, as a material of the vibrator, a
stainless material, especially SUS420J2 or SUS440C being excellent
in abrasion resistance, is used.
[0074] A plate, of which the size L4 is longer than the entire
length L5 (i.e., the dimension in the Y direction) of the vibrator
301 to be manufactured, is prepared and then notched portions or
slits are formed as illustrated in FIG. 4B.
[0075] The height of each of the projection portions can be
arbitrarily set to the desired length by adjusting lengths L1 and
L2 before the processing of the vibrator.
[0076] The notched portions are formed by etching, press-cutting or
the like, and then the projection portions 109 and 110 are molded
by a bending process.
[0077] The shape after the manufacture is resulted as illustrated
in FIG. 4A, and a part of the notch portion becomes the narrow
slit. As just described, the projection portions can be
manufactured by the bending process without almost changing the
thickness of the projection portions 109 and 110 before and after
the manufacture.
[0078] As a result, limitations for the height or the shape of the
manufacturable projection portions can be reduced, differently from
a case of a drawing process or a forging process in which a high
coefficient of extension is required for a plate to be used.
[0079] In addition, a wall portion 34 having high rigidity with the
little decrease in the thickness of the projection portion can be
molded, as compared with the drawing process.
Fourth Embodiment
[0080] As the fourth embodiment, an example of the constitution of
a vibrator in a vibration type driving apparatus characterized by a
mode different from the modes of the above-described embodiments
will be described with reference to FIGS. 5A and 5B.
[0081] In the present embodiment, boundary portions between a base
and wall portions of a projection portion are provided at the same
place as that of phase of a central portion in an upthrust
mode.
[0082] As the upthrust mode, not only a first-order bending mode
but also a second-order or third-order bending mode may be
used.
[0083] For example, in FIG. 5A, the base and a piezoelectric
element are in a third-order bending mode, and the boundary
portions between the base and the wall portions of the projection
portion are located at such a place (position) of which the phase
is the same phase including the central portion in the upthrust
mode. That is, the boundary portions between the projection
portions and the base are located at the place (position), where
the displacement directions of the Z direction (upthrust
direction/normal direction) of the base become the same.
[0084] According to this constitution, as indicated in the first
embodiment, the phases of the two wall portions of the projection
portion and the phase of the central portion of a contact surface
of the projection portion become the same, whereby stable driving
can be obtained. As illustrated in FIG. 5B, two boundary portions
between the base and the wall portions of the projection portion
may be provided unsymmetrically in regard to the center of the
base.
Fifth Embodiment
[0085] As the fifth embodiment, an example of the constitution of a
vibrator in a vibration type driving apparatus characterized by a
mode different from the modes of the above-described embodiments
will be described with reference to FIGS. 6A and 6B.
[0086] In FIG. 6A, connecting portions 59a, 59b, 59c and 59d of
which the rigidity in the Z direction is decreased are provided
between a contact portion 56 and wall portions 54a and 54b, thereby
realizing a stable contact even if the springiness is not given to
a slider.
[0087] An upper surface of the contact portion 56 is provided at a
higher position as compared with positions of upper surfaces of the
connecting portions 59a, 59b, 59c and 59d, and it is constituted
that the slider does not contact with the connecting portions 59a,
59b, 59c and 59d.
[0088] In such the form, since width of the wall portions 54a and
54b and width of the contact portion 56 can be independently set,
it becomes possible to further improve the rigidity in the drive
direction by increasing width of the wall portions.
[0089] A case in FIG. 6B is similar to the above-described case,
connecting portions 59a and 59b of which the rigidity in the Z
direction is decreased are provided between the contact portion 56
and the wall portions 54a and 54b, thereby realizing a stable
contact even if the springiness is not given to the slider.
[0090] An upper surface of the contact portion 56 is provided at a
higher position as compared with positions of upper surfaces of the
connecting portions 59a and 59b, and it is constituted that the
slider does not contact with the connecting portions 59a and
59b.
[0091] In such the form, since width of the wall portions 54a and
54b and width of the contact portion 56 can be independently set,
it becomes possible to further improve the rigidity in the drive
direction by increasing width of the wall portions.
[0092] While the present invention has been described with
reference to the exemplary embodiments, it is to be understood that
the invention is not limited to the disclosed exemplary
embodiments. The scope of the following claims is to be accorded
the broadest interpretation so as to encompass all such
modifications and equivalent structures and functions.
[0093] This application claims the benefit of Japanese Patent
Applications No. 2010-058779, filed Mar. 16, 2010, and No.
2010-261582, filed Nov. 24, 2010, and No. 2011-007695, filed Jan.
18, 2011, which are hereby incorporated by reference herein in
their entirety.
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